Conventionally, compact disks are widely used, wherein music information or other information is recorded as digital signals by the use of pits mechanically formed thereon. These compact disks are designed to be used only for reproducing information.
On the compact disks, there are pieces of information successively recorded, and in reproducing the information, a successive reproduction, selective reproduction, or other forms of reproduction is performed while collating absolute addresses predeterminately recorded on the disk with those recorded in the TOC (Table of Contents) area of the disk for indicating the recording position of each piece of information.
In the case of rewritable disks such as magneto-optical disks, which have been developed recently for recording music information or other information thereon, it is desirable to provide a disk recording and reproducing device which can interchangeably use the rewritable disks and conventional compact disks by using common reproducing methods.
Therefore, likewise in the compact disk, it is proposed to install a TOC area in the rewritable disk in order to record absolute addresses indicating the recording start positions and recording end positions therein and to use the absolute addresses recorded in the TOC area in reproducing each piece of information.
More specifically, when the rewritable disk is placed in the disk recording and reproducing device, by reading the absolute addresses recorded in the TOC area and storing them in the buffer section of a microcomputer, an access to the leading part of desired information may be performed at once in reproduction, and in recording new information, the absolute addresses of the information indicating the recording start position and recording end position thereof are stored in the buffer section. Moreover, when the rewritable disk is removed from the disk recording and reproducing device, the contents of the buffer section are recorded in the TOC area for use in the next reproduction.
Furthermore, in the disk recording and reproducing device having above arrangement for the rewritable disks, it is proposed to display the absolute addresses indicating the recording start position and recording end position of each information on a display part in order to confirm the recorded information.
However, in a disk recording and reproducing device with the above arrangement, if the memory in the buffer section should be lost due to a power cut-off or other malfunction during recording on the rewritable disk or reproducing therefrom, nonconformity might occur between the absolute addresses recorded in the TOC area and the actual recorded positions of the information, and thereafter it would be impossible for the user to accurately recognize the contents of an information recording area wherein information entered from external devices is recorded. As a result, inconvenience might be presented in that information is mistakenly recorded overlapping with the position where necessary information has been recorded.
Moreover, in the rewritable disk, a plurality of information tends to remain on the disk in an unsuccessive state due to such operations wherein a part of information previously recorded has to be erased. In this case, when finding space domains in which to record new information, since the user has to determine the position and length of the space domains according to the absolute addresses of the information previously recorded shown on the display part, the determination tends to be complicated, and consequently, if the user should make a mistake in determining the length or other factors of the space domains, he might erase information previously recorded while recording the new information.
Furthermore, research on an overwriting function for magneto-optical disks or the like for overwriting new information on the range previously recorded has been performed with the arrangement, if overwriting should be mistakenly performed on a range with necessary recorded information, the information would be erased, and whereby a troublesome situation might be caused. Moreover, if a part of or all of the information previously recorded should be erased by overwriting or erasing operation, nonconformity would occur between the contents of the TOC area and the actual position of the recorded information, thereby causing confusion in next accusing the information.